Stephen Hawking is the celebrated Cambridge physicist and author of A Brief History of Time. The following is an excerpt from Hawking's reflections prepared for the White House Millennium Council in 1998 and published in NPQ that year.

Cambridge--Nearly all the visions of the future that we have been shown from H.G. Wells onward have been essentially static. They show a society that is in most cases far in advance of ours, in science, in technology and in political organization. (The last might not be difficult.) There must have been great changes with their accompanying tensions and upsets in the period between now and then. But by the time we are shown the future, science, technology and the organization of society are supposed to have achieved a level of near perfection.

I want to question this picture and ask if we will ever reach a final steady state of science and technology. At no time in the 10,000 years or so since the last Ice Age has the human race been in a state of constant knowledge and fixed technology. Nowhere is this clearer than with genetics.

By far the most complex systems that we have are our own bodies. Life seems to have originated in the primordial oceans that covered the Earth four billion years ago. How this happened we don't know. It may be that random collisions between atoms built up macro-molecules that could reproduce themselves and assemble themselves into more complicated structures. What we do know is that by three and a half billion years ago the highly complicated molecule DNA had emerged. DNA is the basis for all life on Earth. It has a double helix structure, like a spiral staircase, which was discovered by Francis Crick and James Watson in the Cavendish lab at Cambridge in 1953. The two strands of the double helix are linked by pairs of nucleic acids like the treads in a spiral staircase. There are four kinds of nucleic acids. The order in which these different nucleic acids occur along the spiral staircase carries the genetic information that enables the DNA molecule to assemble an organism around it and reproduce itself. As the DNA made copies of itself there would have been occasional errors in the order of the nucleic acids along the spiral. In most cases the mistakes in copying would have made the DNA unable to reproduce itself. Such genetic errors, or mutations as they are called, would die out. But in a few cases the error or mutation would increase the chances of the DNA surviving and reproducing. This natural selection of mutations was first proposed by another Cambridge man, Charles Darwin, in 1857, though he didn't know the mechanism for it. Thus the information content in the sequence of nucleic acids would gradually evolve and increase in complexity.

Because biological evolution is basically a random walk in the space of all genetic possibilities it has been very slow. The complexity, or number of bits of information that are coded in DNA, is given roughly by the number of nucleic acids in the molecule. Each bit of information can be thought of as the answer to a yes-no question. For the first two billion years or so the rate of increase in complexity must have been of the order of one bit of information every hundred years. The rate of increase of DNA complexity gradually rose to about one bit a year over the last few million years. But now we are at the beginning of a new era in which we will be able to increase the complexity of our DNA without having to wait for the slow process of biological evolution. There has been no significant change in human DNA in the last 10,000 years. But it is likely that we will be able to completely redesign it in the next thousand. Of course many people will say that genetic engineering on humans should be banned. But I rather doubt if they will be able to prevent it. Genetic engineering on plants and animals will be allowed for economic reasons, and someone is bound to try it on humans. Unless we have a totalitarian world order, someone will design improved humans somewhere.

Clearly, developing improved humans will create great social and political problems with respect to unimproved humans. I'm not advocating human genetic engineering as a good thing. I'm just saying that it is likely to happen in the next millennium, whether we want it or not. This is why I don't believe science fiction like Star Trek where people are essentially the same 400 years in the future. I think the human race, and its DNA, will increase its complexity quite rapidly.

In a way the human race needs to improve its mental and physical qualities if it is to deal with the increasingly complex world around it and meet new challenges like space travel. And it also needs to increase its complexity if biological systems are to keep ahead of electronic ones. At the moment computers have an advantage of speed, but they show no sign of intelligence. This is not surprising because our present computers are less complex than the brain of an earthworm, a species not noted for intellectual powers.

But computers obey Moore's Law put forward by Gordon Moore of Intel. This says that their speed and complexity double every 18 months. Clearly this cannot continue indefinitely. However, it will probably continue until computers have a similar complexity to the human brain. Some people say that computers can never show true intelligence, whatever that may be. But it seems to me that if very complicated chemical molecules can operate in humans to make them intelligent, then equally complicated electronic circuits can also make computers act in an intelligent way. And if they are intelligent they can presumably design computers that have even greater complexity and intelligence.

This is why I don't believe the science-fiction picture of an advanced but constant future. Instead, I expect complexity to increase at a rapid rate, both in the biological and electronic spheres. Not much of this will happen in the next hundred years, which is all we can reliably predict. But by the end of the next millennium, if we get there, the change will be fundamental.